How do you steal friends?

if u want the best way then here it is: you should hang out with the friend u want to steal. but the idea is to not do it so obvious.
i mean like 4 me, i would take advantage of everything and just act cool or act like the person Ur going to steal.
for example's hang out with that person u want 2 be Ur bf.
oh, and when u steal that person, make sure that Ur not being obvious 'cause if u do, then the person u want to steal best friend could take advantage of you that quick without u knowing.